1. Field of the Invention
The present invention relates to a spindle-driving device for winding machines and similar textile machines, in which the spindle is supported rotatably by a cylindrical cartridge held by elastic thrust means acting radially and peripherally around the cartridge itself, between the latter and a fixed support element, and in which the spindle is connected to an electric drive motor.
2. Description of the Related Art
From U.S. Pat. No. 4,731,985, a spindle for textile machines is supported rotatably by a cartridge held radially by elastic thrust means arranged peripherally both to dampen the vibrations to which a textile spindle is normally subjected, and to facilitate application and removal of the spindle itself without having to remove the entire support device.
In general spindles on a textile machine are driven by means of a mechanical transmission formed substantially by a tangential belt which extends for the whole length of the machine and which is pushed, by means of idle rollers, against the corresponding pulleys of the spindles.
The tangential belt drive for a whole assembly of spindles is commonly used on textile machines which work at relatively low speeds. The current tendency to increase spindle rotation speeds considerably to reach 30,000 r.p.m. and over has been found to be impossible with belt drives due to the loud noise generated by the mechanical transmission and the high consumption of energy necessary for driving rotation of the spindles, a consumption which rises progressively and exponentially as the rotation speed of the spindles themselves increases. Moreover, with tangential belt drives, special and complex techniques are required to keep the drive belt away from the pulley of each individual spindle, when the latter has to be stopped for example to repair a broken thread, without having to stop the entire textile machine.
U.S. Pat. No. 4,348,860 introduces the use of electric drive motors for each individual spindle, powered at high frequency to reach the high working speeds required. Nevertheless the constructional solutions proposed hitherto make the application of spindles and their removal for routine maintenance, required by the rotating mechanical parts with a certain frequency, extremely difficult. Moreover the use of an electric motor for each spindle, according to the ideas previously known, is not suitable for application to spindles supported oscillatingly, for example according to the support device shown in U.S. Pat. No. 4,731,985 cited previously. Any relative movement between the rotor and stator of the electric motor could bring the two parts into contact, damaging them irreparably.